I asked Feliks whether Envy was OK with a 6V input and they side it will be fine but 2V is preferable
Is there even a high end DAC without preamp that has a (fixed) output of 2v or less? Looks to me the use of a preamp (module) is the best option.
Just ordered them, Ill let you know -> no matter what it will be bliss going from a defect WE300B to all working tubes plus the Brimars -> probably wouldn't have gone down this upgrade route if everything was working from the get go haha
I made the experience that the 300Bs make the most difference. To be honest, I bought the Brimar 1988s (also brown base, transparent ones) mainly because of looks

But I got a very good deal and only paid 200 EUR for a used pair. NOS Red Base RCAs incoming, as well. Also bought mainly for looks and as spares for the Brimars. I don’t expect much of a sonic difference, either.
The problem with comparing tubes is audio memory. It obviously takes a long time to change tubes and listen again if you don’t have 2 equal amps with different tube settings plus driver tubes differences are not that obvious. That’s why it is great
@Exekuhtor was able to compare just like that.
All the experienced tube fans say that the Brimars are good, so you will be fine
Voltage might not be a problem explicitly, but the gain is - mid/high are so vast that the pot has to be turned all the way down (8 o’clock!), which hurts the sonics and dynamic range. It’s a shame that is the most generic potentiometer, not some nice stepped one. With May directly low gain would be okay volume wise with abyss, but it chokes. Now I just set up Envy to 2 o’clock high gain and control with the remote from a chair
That is one reason why I wanted to have the Spring. It has the option to be upgraded with a top notch preamp module + a great remote control. I sit 2m+ from my system so a remote is perfect for me.
That's one of the three flaws of the Envy.
The potentiometer makes the unit too loud too quickly - people almost only use the first third. Solution: Use a preamp.
The gain / input knobs are wobbly. Solution: Don't touch it.
Medium and high gain are not that different, medium gain should be lower and low gain should also be lower. You mostly only get a higher noisefloor with high gain. Solution: Don't use high gain, use mostly low gain, for hard to drive stuff switch to medium.
Do you use your Immanis on Mid gain, too?
So, unlike some others here, you are not suffering from knob wobble.
I belong to the members with the beautiful knob wobble feature! Honestly, who cares? It’s not super tactile but therefore it represents a perfect analog character!